Urth blinked. 'First, I want to make it perfectly plain that the important thing is mass transference. It can still be recovered.'
Mandel, scowling still, said querulously, 'What the devil are you talking about, Urth?'
The man who scanned the paper probably looked at what he was scanning. I doubt that he had the time or the presence of mind to read it, and if he did, I doubt if he could remember it... consciously.
However, there is the psycho-probe. If he so much as glanced at the paper, what impinged on his retina could be probed.'
There was an uneasy stir.
Urth said at once, 'No need to be afraid of the psycho-probe. Proper handling is safe, particularly if a man offers himself voluntarily. When damage is done, it is usually because of unnecessary resistance, a kind of mental tearing, you know. So if the guilty man will voluntarily confess, place himself in my hands-'
Talliaferro laughed. The sudden noise rang out sharply in the dim quiet of the room. The psychology was so transparent and artless.
Wendell Urth looked almost bewildered at the reaction and stared earnestly at Talliaferro over his glasses. He said, 'I have enough influence with the police to keep the probing, entirely confidential.'
Ryger said savagely, 'I didn't do it.' Kaunas shook his head.
Talliaferro disdained any answer.
Urth sighed. 'Then I shall have to point out the guilty man. It will be traumatic. It will make things harder.'
He tightened the grip on his belly and his fingers twitched. 'Dr. Talliaferro indicated that the film was hidden on the outer window sill so that it might remain safe from discovery and from harm. I agree with him.'
'Thank you,' said Talliaferro dryly.
'However, why should anyone think that an outer window sill is a particularly safe hiding place? The police would certainly look there.
'Even in the absence of the police it was discovered. Who would tend to consider anything outside a building as particularly safe? Obviously some person who has lived a long time on an airless world has had it drilled into him that no one goes outside an enclosed place without detailed precautions.
To someone on the Moon, for instance, anything hidden outside a Lunar Dome would be comparatively safe. Men venture out only rarely and then only on specific business. So he would overcome the hardship of opening a window and exposing himself to what he would subconsciously consider a vacuum for the sake of a safe hiding place. The reflex thought, Outside an inhabited structure is safe, would do the trick.'
Talliaferro said between clenched teeth, 'Why do you mention the Moon, Dr. Urth?'
Urth said blandly, 'Only as an example. What I've said so far applies to all three of you. But now comes the crucial point, the matter of the dying night.'
Talliaferro frowned. 'You mean the night Villiers died?'
'I mean any night. See here, even granted that an outer window sill was a safe hiding place, which of you would be mad enough to consider it a safe hiding place for a piece of unexposed film? Scanner film isn't very sensitive, to be sure, and is made to be developed under all sorts of hit-and-miss conditions.
Diffuse nighttime illumination wouldn't seriously affect it, but diffuse daylight would ruin it in a few minutes, and direct sunlight would ruin it at once. Everyone knows that.'
Mandel said, 'Go ahead, Urth. What is this leading to?'
'You're trying to rush me,' said Urth, with a massive pout. 'I want you to see this clearly. The criminal wanted, above all, to keep the film safe. It was his only record of something of supreme value to himself and to the world. Why would he put it where it would inevitably be ruined almost immediately by the morning Sun? Only because he did not expect the morning Sun ever to come. He thought the night, so to speak, was immortal.
'But nights aren't immortal. On Earth they die and give way to daytime. Even the six-month polar night is a dying night eventually. The nights on Ceres last only two hours; the nights on the Moon last two weeks. They are dying nights too, and Drs. Talliaferro and Ryger know that day must always come.'
Kaunas rose. 'But wait-'
Wendell Urth faced him full. 'No longer any need to wait, Dr. Kaunas. Mercury is the only sizable object in the Solar System that turns only one face to the Sun. Even taking libration into account, fully three-eights of its surface is true dark-side and never sees